Barriers and facilitators to type 2 diabetes management among slum‐dwellers: A systematic review and qualitative meta‐synthesis

Abstract Background and Aims The prevalence of type 2 diabetes (T2D) is on the rise worldwide, especially in developing countries. There is a significant difference between the slum‐dwellers and other urban dwellers in terms of T2D incidence rate and access to healthcare services. This review aimed to identify barriers and facilitators to T2D management among slum‐dwellers. Methods A systematic review was conducted to identify barriers and facilitators to T2D management from January 1, 2002 to May 30, 2022. We searched MEDLINE via PubMed, Scopus, Web of Sciences, and Google Scholar. The inclusion criteria were: qualitative or mixed‐methods research, published in English, focused on slum‐dwellers and T2D or its complications, and assessed barriers and facilitators to T2D management among slum‐dwellers. Quality appraisal was conducted using the QATSDD critical appraisal tool. A thematic approach was used for data analysis and synthesis. Results A total of 17 articles were included in this review. Three analytical themes were identified: (1) Individual factors consisting of four themes: lifestyle behaviors, informational, psychological, and financial factors; (2) Health system factors consisting of three themes: patient education processes, financial protection, and service delivery; and (3) Contextual factors consisting of three themes: family support, social support, and environmental factors. Conclusion Our review disclosed that the individual, health system, and context influence T2D management among slum‐dwellers. Policymakers can use the findings of this review to reduce barriers and augment facilitators to improve healthcare utilization and self‐care management among patients with T2D in slums.


| INTRODUCTION
Slum-dwellers are socioeconomically and environmentally disadvantaged. 1 According to the United Nations Human Settlements Program, in low-and middle-income countries (LMICs), nearly 863 million people are estimated to be living in slums. 2 Slums are an important part of today's urban settlements. 3,4 The United Nation Program on Human Settlement has defined slums in 2002 as: "a contiguous settlement where the inhabitants are characterized as having inadequate housing and basic services. A slum is often not recognized and addressed by the public authorities as an integral or equal part of the city." 5 In detail, a slum is an urban area characterized by poor health outcomes, low access to health services, low housing situation, poor social services, inadequate basic facilities, insecurity, poor livelihood, unstable incomes, overcrowding, poor sanitation infrastructure, and limited access to safe water. 3,4,6 Type 2 diabetes (T2D) is among the most prevalent noncommunicable diseases (NCDs) globally. 7 The total number of people living with diabetes is predicted to rise to 643 million by 2030 and 783 million by 2045. 8 A total of 75% of diabetic patients live in developing countries. The prevalence, risk factors, and complications of T2D are higher among the disadvantaged population, 9 including slum-dwellers.
A study in India demonstrated that the prevalence of people at high risk for diabetes was high in the slum population, and primary education, low socioeconomic status, less physical activity, and high waist circumference were major contributing factors to diabetes. 10 Also, a study in Brazil showed the prevalence of T2D was higher among slum-dwellers compared to the general population (10.1% vs. 5.2%). 11 Despite the high level of healthcare needs, slum-dwellers are less likely to seek and use healthcare services than the nonslum population in the cities. 12,13 For instance, it has been shown that slum-dwellers have lower healthcare utilization in antenatal services 12 and also NCDs services 13 compared with the general population. Given that slum-dwellers are a population with specific needs and are at higher risk for the incidence of T2D and its complications, the management of T2D among this population should be taken into account specifically. Slum-dwellers face more challenges and barriers to better management of T2D. Identifying barriers and facilitators to T2D management can assist policymakers in augmenting facilitators and modifying barriers to improve healthcare utilization among different communities of slum-dwellers. This review aimed to comprehensively identify T2D management barriers and facilitators among slum-dwellers.

| Data sources and search strategy
To conducting this systematic review, we searched MEDLINE via PubMed, Scopus, and Web of Sciences from January 1, 2002 to May 30, 2022 using the following keywords: facilitators, barriers, management, health-seeking, adherence, compliance, utilization, T2D, and slum-dwellers. To conduct a comprehensive search, synonymous terms were found using mesh terms. Google Scholar was searched for relevant articles. Gray literature was also searched.
In addition, we searched the reference lists of all included studies to identify additional relevant studies. The full search strategy and keywords can be found in Appendix 1.

| Eligibility criteria
The articles were included if they (1) published between January 1, 2002 (slum-dwellers was defined based on the United Nations) and May 30, 2022, (2) focused on slum-dwellers, (3) focused on T2D or its complications, (4) used a qualitative approach or mix-method approach, and (5) examined barriers or/and facilitators to T2D management in slum-dwellers. Articles that were not published in the English language were excluded.

| Study selection
All duplicate articles were removed using the EndNote reference management software, and two independent reviewers (F. G. and H. J.) reviewed the titles and abstracts of retrieved articles for eligibility.
After removing the irrelevant articles, the full-text studies were independently assessed for eligibility by the two researchers. In the case of disagreement in the selection process, each disagreement was resolved by discussion with the third independent researcher.

| Data extraction
Once the article was deemed to be eligible, data were extracted independently and summarized by two researchers (F. G. and M. G.) and checked by a third reviewer (H. J.). A standard form was developed for data extraction. Extracted details included author (year), location, quality assessment, objective/s, design, sample size (participants), data collection methods, age and sex, literacy level, race barriers, and facilitators (Tables 1 and 2). We defined barriers as any factors that their absent/presence impede slum-dwellers from managing their diabetes properly. In our definition of facilitators, we refer to factors that their presence promotes the management of T2D.

| Analysis and synthesis
We used qualitative thematic synthesis for data analysis, as proposed by Thomas and Harden. 32 This thematic synthesis analysis has three stages 1 : the coding of text "line-by-line," 2 the development of "descriptive themes," and 3 the generation of "analytical themes." We first used an inductive approach to coding and to create new themes and then complimented the process with a deductive approach to categorize codes. In this review, stages 1 and 2 were concurrently conducted by two reviewers. In the development of the primary synthesis, two independent reviewers (F. G. and M. G.) undertook a lineby-line review of each study's results and discussion and extracted initial codes. Coding was based on explicit and implicit responses to the study question. Next, identified codes were compared based on their similarities and differences. After the agreement between reviewers about codes, similar codes were grouped, and descriptive themes were developed accordingly. The name of each descriptive theme was chosen with the agreement between reviewers and derived based on the most common meaning conveyed by the codes across studies. This iterative process was continued until saturation of themes and codes and agreement was achieved between reviewers. After that, the themes were examined in terms of similarity and differences, and the similar descriptive themes were categorized in an analytical theme. To develop analytical themes, we generated new interpretive constructions beyond the primary studies. The analytical themes were developed by two independent reviewers. Then, decision-making about analytical themes was discussed among reviewers, and the nomination of analytical themes was discussed among reviewers.

| Credibility and trustworthiness
Triangulation and peer debriefing strategies were used to address credibility and trustworthiness. 33,34 To this end, coding, appraisal, data analysis, and synthesis of studies were conducted by two researchers, independently. Also, discrepancies were resolved through consensus among four researchers. The codes, descriptive themes, and analytical themes were subsequently assessed by two researchers outside of the study.
This systematic review was conducted in accordance with PRISMA 2020 guidelines.

| Study selection
As shown in Figure 1, 7114 articles were retrieved from the search strategy. After the removal of duplicates, titles, and abstracts of 5460 articles were screened, and 5329 irrelevant articles were excluded.
By assessing the full text of the remaining 131 articles, 107 that did not fulfill inclusion criteria were excluded. Finally, 17 articles met the eligibility criteria and were included in the thematic synthesis.

| Study characteristics
The study characteristics of the included studies are summarized in Table 1. The studies were published between 2004 and 2021. Of the included studies, 15 studies were qualitative studies, and two studies were undertaken using mixed-or multimethod. Data collection methods for qualitative studies were focus group interviews, semistructured interviews, in-depth interviews, or structured qualitative groups. The sampling methods were purposeful or convenience.
Except for one paper, the rest of the studies were conducted from patients' perspective. The quality assessment results showed that four articles had "high quality," and 13 had "moderate quality." Most of the included studies were carried out in the USA (n = 7), India

| Barriers and facilitators to T2D management
As shown in Table 3

Service delivery
Regarding service delivery, the studies reported the importance of accessibility, availability, quality of care, and patient-provider relationships. 14,15,[17][18][19][20][21][22][23][24][25][26][27]29,30 Patientprovider/physician relationship was commonly found to influence disease management. 14,15,24,25,29,30 Poor communication with providers may hinder medication adherence. 25 Communication barriers between the providers, patients, and organization, and difficulty accessing primary care often results in patients forgoing needed care. 24 Fragmented healthcare delivery was reported as a barrier to continuing treatment in India. 22 The healthcare professional can help diabetic patients to overcome the barriers to selfmanagement, such as lack of family support, negative perception of time, and so on. 16 An Australian study showed that when healthcare professionals personalize care, develop rapport and express empathy, more effective care can be delivered. 15

Contextual factors
The most important themes related to contextual factors were: (1) family support, (2) social support, and (3) environmental support.

Family support
This included family size, generation gap, gender discrimination, information, reminding to take medicine, and psychological factors. 14,[16][17][18][20][21][22][23][24][25]28,29,35 Several studies reported the important role of family members, particularly spouses and children, in diabetes selfmanagement, and also were seen as a facilitator to adherence/diet and a source of information. 14,17,26,28,29 A qualitative study found that although family support could positively influence diabetes self-management among patients, the fear of becoming a burden on the family may limit these positive impacts. 14 Being dependent on family members to obtain medications or having responsibilities to the family interfered with diabetes self-management, and some patients felt isolated from their family members. 29 A study reported cultural beliefs and values could influence the perceived feelings of despair and isolation from family members, while another study reported that culture did not seem to have an impact on the attitudes and behaviors to diabetes self-management. 35

Social support
These included social isolation, stigma, and peer groups. overweight, such as stigma, health problems, and negative effects on personal relationships, but obesity was also seen as a sign of happiness, wealth, and a genetic origin. 19 Social support networks can mediate the impacts of economic and environmental disadvantages by improving access to social capital. 14

Environmental factors
Regarding "environmental factors," 15,17,19,20,30 the authors recognized the importance of neighborhood safety and a supportive environment to disease management.
Unsafe environments to exercise and go to health centers were complaints by slum-dwellers patients with T2D. 15 Barriers to physical activity could be related to a lack of willingness and resources to exercise and a social upbringing, especially where there was no opportunity to exercise. 19

| DISCUSSION
This study aimed to identify barriers and facilitators to T2D management in slum residents by synthesizing qualitative studies.
We found 17 studies on the facilitators and barriers to T2D management among slum-dwellers. We identified three analytical GHAMMARI ET AL. | 11 of 15 themes, including individual factors, contextual factors, and health system-related factors to T2D management in slum-dwellers.
We identified several factors that are particularly pertinent in slum settings, such as difficulty in dietary adherence, adherence medication, [15][16][17][18]26 lifestyle changes/behavior, 15,16,18,22,23,26 literacy and knowledge about the disease and diet, 14,15,[17][18][19]26,30,35 costs and financial issues, 14,[17][18][19][21][22][23][24][25]27,29,35 family/social/friends support, 14,25,26,29 availability/accessibility of healthcare services, the costs of health services, 15,[17][18][19][20]23 patients-providers interaction. 14,24,25,29,30 In line with our study, a previous scoping review suggested that factors such as knowledge, perception (including misconception and distrust), financial issues, stigma, healthcare needs and health services, competing priorities and inadequacy of social support, and so on, in the existing health system all contribute to the challenges faced by slum-dwellers. 39 Costs and financial issues were frequently reported in studies as factors affecting healthcare-seeking behaviors, disease management, and also as a barrier to dietary adherence and eating healthy food, adherence to medication, and diabetes self-management. 14,[17][18][19][21][22][23][24][25]27,29,35 These barriers were also reported in previous studies. [40][41][42] A study in Iran reported financial issues being the main reason for not taking prescribed drugs. 43 According to a cross-sectional study in Iran, 45% of patients were forced to forgo treatment because of financial barriers and treatment quality discontent. 44 It seems that the measures to provide financial protection for health to this group need to be complemented and integrated with broader social protective measures that promote livelihoods and other social services. 22 Literacy and knowledge about the disease, how to diet, or how to eat were frequently reported in studies as both facilitators and barriers. 14,15,[17][18][19][20]24,26,29,30,35 Health literacy was found to be poorer among older people, minority groups, and people from lower socioeconomic circumstances. 45 Living in slums has been found to be associated with poor knowledge about the cause and preventability of diseases 46 and also a barrier to accessing healthcare services. 47,48 Poor health literacy and knowledge can limit patients' ability to care for their medical problems. 35 Educational interventions can reduce diabetes incidence by 54% through a reduction in fasting blood glucose, body mass index, and waist circumference. Regardless of educational intervention duration, the diabetes risk parameters may improve at as low as 6 months. 49 Some identified facilitators in studies were education in a narrative form, 15 providing education and support within the family context, community settings, and social groups, 29 delivering pamphlets, 26 receiving education from healthcare providers 20 and trained facilitators (e.g., retired nurses), 19 availability of different education modalities, 26 culturally and linguistically appropriate education and intervention, 29,30 and community-based and family-centered education. 30 More community-based education regarding T2D self-management and treatment, with peer group education and the use of trained facilitators, were seen as facilitators. 19 Socio-environmental, cultural factor, 17 and patients' perceptions regarding the disease can impede lifestyle behaviors. 18 The available literature demonstrated that lifestyle changes with physical activity could alter the incidence of diabetes or one of the T2D risk factors. 50 Reasons causing patients with T2D in slum areas to stop physical activity were fear of public ridicule, comorbidities, 17 laziness, 19 fear of walking in the street, 15 and maintaining this as a habit is a tricky part of life as a habit. 16  Family support can play a crucial role in diabetes selfmanagement. 29 Family members can act as a support system for medication adherence and as a health information source. 25,53,54 One reason that causes family members don't support patients with diabetes is their lack of knowledge about the disease. 29 Jackson et al.
reported that while family, culture, and religion were strong positive influences on health behaviors, poor health-care access, and patientprovider interactions adversely impacted self-care ability. 24 Slum-dwellers frequently reported a lack of health services and insufficient availability and accessibility of healthcare services as barriers. 17 After completing the meta-synthesis, we compared studies with high and moderate quality in terms of relative contributions to analytical themes but found no difference.

| STRENGTHS AND LIMITATIONS
Our study has strengths and limitations that deserve to be in the study design, collection, analysis, and interpretation of data, writing of the report, or the decision to submit the report for publication.

CONFLICT OF INTEREST STATEMENT
The authors declare no conflict of interest.

DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.

ETHICS STATEMENT
This study was part of the PhD thesis of F. G. and was approved by the

TRANSPARENCY STATEMENT
The lead author Masumeh Gholizadeh affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.